Recently, electrophotographic technology is being widely employed not only in the copier field but also in the printer field, as a high quality image can be instantly obtained with such technology. At the core of the electrophotographic technology is a photoconductor. Particularly, currently an organic photoconductor using an organic photoconductive material that causes no pollution, that can easily form a film and that can be easily manufactured is now popular.
Furthermore, among organic photoconductors, a functionally separated photoconductor that has a photosensitive layer formed by laminating a charge generating layer and a charge transporting layer is widely used. The functionally separated photoconductor is widely used because it provides several advantages over other types of photoconductors. First, it provides high sensitivity due to the combination of a highly effective charge generating substance and charge transporting substance. Second, it exhibits reliable performance and can be manufactured using widely available materials. Third, it is easy to manufacture at reasonable cost.
A mechanism for forming an electrostatic latent image in the functionally separated photoconductor is described. At first, when a photoconductor is photo-irradiated after charging, light passes through a charge transporting layer and is absorbed by a charge generating substance in a charge generating layer, and a charge is thereby generated. Then, the generated charge is injected into the charge transporting layer at an interface between the charge generating layer and the charge transporting layer. The charge then moves through the charge transporting layer to a surface by an electric field and forms the electrostatic latent image by neutralizing the charge on the surface of the photoconductor, as disclosed in Japanese laid-open patent application number 2002-318459.
Present image reproduction applications require high-speed formation of a high-quality picture of an image. To realize such high-speed, high-quality picture formation, toner material must be improved to include an external additive, such as silica, to control charging, to impart liquidity, and to upgrade transferring efficiency.
However, a problem known as “filming,” which is a phenomenon by which toner accumulates on a small scratch on the surface of the photoconductor and thereby deteriorates a resulting print image, becomes increasingly obvious when the speed of image formation is increased in a traditional photoconductor. The small scratch is typically generated by an external stress, such as pressure from a cleaning blade, on a surface of the photoconductor, and the number of scratches is sharply increasing as the image formation process becomes faster. Also, micro particles in the external additive in the toner adhere to the scratch and form a core. Filming then occurs as silica that is included in the external additive of the toner adheres to and accumulates in the core. When filming occurs in this manner, the formed image quality is degraded since the toner corresponding to a print image cannot adhere to the corresponding part of the photoconductor and a dead pixel occurs.
The purpose of the present invention is to provide an electrophotographic apparatus, a developing device and an image forming device that can inhibit the occurrence of filming, and that can form a high-quality image at high speed without degrading the image quality, by solving the traditional problems and by forming a plurality of bumps that are sloped with respect to the circumferential direction on the photoconductor surface.
For the purpose, the present invention is related to an electrophotographic apparatus includes, a photoconductor, a plurality of a series of bump portions formed on a surface of the photoconductor, the bump portions having slopes with respect to a circumferential direction of the photoconductor, and each of the bump portions being spaced apart by a predetermined interval from adjacent bump portions with respect to the circumferential direction.
In the present invention, a plurality of bumps that are sloped with respect to the circumferential photoconductor direction are formed successively on a surface of an electrophotographic apparatus. With this configuration, the filming can be prevented, and a high-quality image can be formed at high speed without degrading the image quality.